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Assets, usually stocks, bonds, and other investments, that have been segregated and restricted (usually in a trust) to provide benefits, at their fair value as of the measurement date. Plan assets include amounts contributed by the employer (and by employees for a contributory plan) and amounts earned from investing the contributions, less benefits paid. If a plan has liabilities other than for benefits, those non-benefit obligations may be considered as reductions of plan assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 30

-Section 35

-Paragraph 50

-URI http://asc.fasb.org/extlink&oid=6867990&loc=d3e12355-114930

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 87

-Paragraph 49

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5

-Subparagraph d(iv)(b)(i)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=21915506&loc=d3e1928-114920

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- Definition

Target allocation of investments of this type to total plan assets presented on a weighted average basis.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (d)(i)

-URI http://asc.fasb.org/extlink&oid=21915506&loc=d3e1928-114920

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 5

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-URI http://asc.fasb.org/extlink&oid=21915506&loc=d3e2446-114920

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- Definition

Target allocation maximum percentage of investments of this type to total plan assets presented on a weighted average basis.

+ References

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Target allocation minimum percentage of investments of this type to total plan assets presented on a weighted average basis.

+ References

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- Definition

Percentage of fair value of investments (categorized by debt securities, equity securities, real estate and other plan assets) to the fair value of plan assets held.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 5

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=21915506&loc=d3e2446-114920

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

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-URI http://asc.fasb.org/extlink&oid=21915506&loc=d3e1928-114920

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5

-Subparagraph d(1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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Benefit Plans (Allocation of Plan Assets) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocations	100.00%	100.00%
Fair value of pension plan assets	251.0	213.3
Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	249.7	212.0
Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	1.3	1.3
Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocations	65.00%	68.00%
Target allocation	65.00%
Allocation range minimum	60.00%
Allocation range maximum	70.00%
Indexed Mutual Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	111.4	102.2
Indexed Mutual Funds [Member] \| Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	111.4	102.2
Indexed Mutual Funds [Member] \| Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets
Indexed Mutual Funds [Member] \| Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets
International Mutual Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	49.6	40.0
International Mutual Funds [Member] \| Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	49.6	40.0
International Mutual Funds [Member] \| Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets
International Mutual Funds [Member] \| Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets
Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocations	34.00%	31.00%
Target allocation	35.00%
Allocation range minimum	30.00%
Allocation range maximum	40.00%
Other [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocations	1.00%	1.00%
Target allocation	0.00%
Allocation range minimum	0.00%
Allocation range maximum	5.00%
Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0.2
Cash [Member] \| Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0.2
Cash [Member] \| Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets
Cash [Member] \| Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets
Mutual Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	83.8	65.6
Mutual Funds [Member] \| Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	83.8	65.6
Mutual Funds [Member] \| Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets
Mutual Funds [Member] \| Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets
Insurance Contract [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	1.3	1.3
Insurance Contract [Member] \| Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets
Insurance Contract [Member] \| Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	1.3	1.3
Insurance Contract [Member] \| Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets
Balanced Mutual Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	4.9	4.0
Balanced Mutual Fund [Member] \| Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	4.9	4.0
Balanced Mutual Fund [Member] \| Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets
Balanced Mutual Fund [Member] \| Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets